As Langer summed it up while she addressed the LeadingAge General Session in Nashville, the 1976 study showed that nursing home residents tended to live longer if they were responsible for taking care of a plant. The finding shows the strength of the mind-body connection, which at that time was dismissed, Langer concluded. And it is in this framework that the study is “still being widely cited in the media and undergraduate psychology textbooks,” Coyne wrote.

The Penn professor has many gripes with the study.

For one, he says Langer's experiment was a product of its time. The 1970s was an era in which high-profile researchers like Stanley Milgram conducted flashy but scientifically flimsy studies, plagued by problems such as small sample sizes and a lack of rigorous controls. Coyne admits he did some of this type of research himself, and classifies Langer's small nursing home experiment — it involved only 45 participants — as this kind of work as well.

Most damning, an erratum statement later added to the study corrected one of its calculations. The result? The whole conclusion became shaky, as the authors acknowledged: “The outcome is therefore only marginally significant, and a more cautious interpretation of the mortality findings than originally given is necessary.”

Google calculates that the plant study has been cited 848 times in other scholarly work but the erratum statement has been cited only six times, Coyne pointed out.

He didn't directly address why the erratum is so overlooked, but his blog basically put forward two possibilities. One is that Langer herself is an “incessant” self-promoter who “has played no small part in preserving and extending” her findings. But he also implicates her audience, saying that people really want to believe the ideas she is peddling, that we can basically think ourselves to better health and longer lives.

Coyne is totally dismissive of this notion. A recent New York Times spread on Langer — “What if age is nothing but a mind-set?” — was full of “hype and hokum,” he wrote. Some of her most recent claims — about how diabetics can lower their blood sugar by distorting their sense of time — are “shocking.” Overall, she is a figure of “tooth fairy science.”

Listening to Langer's talk at LeadingAge, I was interested but skeptical. Reading Coyne's blog made me feel like I had been totally duped to even take her seriously for a second. I had to remind myself that Coyne himself has an axe to grind and a reputation to burnish. He is a “widely published bird dog of pseudoscience,” according to the Times article on Langer, which quoted him as a dissenter. So if Langer is on one extreme in the world of Ivy League psychologist/scientists (she's at at Harvard), Coyne's on the other.

Given that I'm not an Ivy League researcher myself, I won't attempt to split the difference between Langer and Coyne and describe some reasonable middle ground, although I suspect it might be wise to do so. Instead, let me humbly submit this observation: Coyne makes it sound like people believe Langer strictly out of wishful thinking, but I think it might be because her ideas actually match what we experience in our real lives.

Take my own recent experiences. I've been housesitting for the last few weeks, taking care of a dog named Daisy Mae, a cat named Matilda and, yes, plants. In my own apartment, I have no plants or pets, and I can see why getting some might improve my health — for reasons that Coyne would understand and endorse. At my own home, I never fill up a large watering can and then stoop and bend and reach to pour it out. I do not go for a 10-minute walk every morning and a longer walk every evening. I do not ever have to chase after a cat that has slipped out the door and into the bushes.

Doing these things is the “modification of health-related behaviors” that Coyne believes could explain why nursing home residents do better with plants or with pets.

But do I believe that my health only would improve because of these activities? As I packed up my things and prepared to end my housesitting stint this morning, Daisy Mae reacted with alarm. Seeing her face in the window of the house as I threw my bag in the trunk of my car, I felt sad. I'll miss having her company while I watch TV, will miss Matilda curling up at the foot of the bed. Does it seem completely ridiculous that losing this companionship would be worse for my health than losing the extra walks? No.

It's only a feeling that the pets and plants may have improved my health in mysterious ways, having nothing to do with the extra cardio or stretching that their care demanded. Yet this feeling is strong. Maybe Langer can't explain the mind-body connection to Coyne's satisfaction, maybe she is promoting some half-baked ideas, but I think she's appealing to the extent that she's taking this feeling seriously as a scientist.

So were we treated to a crackpot at LeadingAge? Given her famous study, I say let's call her a “flowerpot” instead, and let's keep those raised beds coming.